1. Field of the Invention
The present invention relates to an automatic central buffer coupling for a vehicle, a rail-mounted vehicle in particular, including a coupling head, a coupling rod connected to the coupling head, a bearing block to which the vehicle-side end of the coupling rod is articulated so as to be horizontally pivotable, a fixing plate preferably attachable to the underframe of the vehicle to secure the central buffer coupling to the vehicle, and a shock absorber having a destructively-configured force-absorbing member in the form of a deformable tube with its coupling head-side end against the bearing block and its vehicle-side end against the fixing plate, whereby the shock absorber includes a bolted connection which axially braces the bearing block, the deformable tube and the fixing plate, and upon excessive impact, i.e., upon a predefinable operating load for the central buffer coupling being exceeded, permits an axial displacement of the bearing block relative the fixing plate.
2. Description of the Related Art
Existing central buffer couplings, in particular in the field of railway technology, serve to transfer tensile and compressive forces impacting a car body of a first vehicle from the car body to a neighboring second vehicle when the central buffer coupling is coupled to a central buffer coupling of the second vehicle.
In order to ensure cushioning of the tensile and compressive forces occurring during normal vehicle operation, and transferred, for example, in the case of a multi-member vehicle, between the individual car bodies during the normal vehicle operation by the central buffer coupling, a normally regeneratively-configured drawgear is customarily provided in the coupling rod and/or in the bearing provided to articulate the coupling rod to the bearing block. The drawgear is usually designed to accommodate tensile and compressive forces up to a defined magnitude and relay any forces exceeding that to the vehicle underframe.
Thus, while tensile and compressive forces which occur during normal vehicle operation are cushioned by the drawgear, once the operating load of the drawgear is exceeded, however, for instance, upon the vehicle colliding with an obstacle or upon the vehicle abruptly decelerating, there is the risk that the normally regeneratively-configured drawgear and conceivably also the coupling link between the individual car bodies, the interface between the individual car bodies respectively, will be destroyed or damaged. In any case, the drawgear is inadequate to absorb the whole of the resultant force. Hence, the drawgear is then not integrated into the force-absorbing concept of the vehicle as a whole such that the resulting impact force is transferred directly to the vehicle underframe. Doing so subjects the same to extreme loads and may possibly damage or even destroy the same. With multi-member rail vehicles in such cases, there is the risk of car body derailment.
Frequently used with the objective of protecting the vehicle underframe against damage from strong rear-end impacts, is a shock absorber including a destructively-configured force-absorbing member, for example, in the form of a deformable tube, whereby the force-absorbing member of this shock absorber is designed so as to be activated when the operational absorption of the drawgear is exhausted, and will absorb and thus, dissipate at least a portion of the force transferred through the force-absorbing member in the force flow. In the case of a shock absorber including a destructively-configured force-absorbing member in the form of a deformable tube, the deformable tube is plastically deformed in a defined and destructive manner such that the resulting impact force is at least partly converted into deformation work and heat.
Thus, the problem relates to an automatic central buffer coupling of the type cited above, i.e., including a shock absorber having a destructively-configured force-absorbing member, which frequently needs to have the additional functionality of the central buffer coupling being displaceable in the axial direction, i.e., in the longitudinal direction of the vehicle, between a first extended position, in which the coupling head of the central buffer coupling is in the coupling plane of the vehicle and thus, ready to be coupled, and a second retracted position in which the coupling head is in a position rearward of the coupling plane close to the vehicle.
This additional functionality can, for example, be necessary when the central buffer coupling is utilized in a high-speed train. This type of train is characterized by its end car frequently being built according to optimized aerodynamic observations in terms of the vehicle dynamics. Specifically, the nose cone of such a vehicle, the end car respectively, is frequently manufactured in accordance with aerodynamic specifications, with the objective of reducing cross-wind sensitivity, bow wave and so-called sonic booms.
A preferably glass-fiber reinforced nose cone is usually utilized in order to accommodate the aerodynamic requirements, the nose cone including, for example, a pneumatically-openable front hatch, whereby the automatic central buffer coupling with the shock absorber as well as the actuating mechanism for the front hatch and further components such as for instance signal lights and air ducts for climate control are disposed in the nose cone. The shell of the nose cone itself, made from reinforced glass fiber, for example, is often supported on a supporting structure which itself is in turn bolted to the car body structure. This supporting structure can also serve as the fixing base for the e.g., pneumatically-operating actuating mechanism of the front hatch or a front lifeguard pilot (if provided).
So that two such end cars configured according to the aerodynamic concept can be coupled/uncoupled as quickly as possible, the profiling to the nose cone calls for a coupling concept which ensures a specific axial distance for the extendable automatic central buffer coupling in conjunction with the e.g. pneumatically-actuated front hatch. The distance to be provided is—contingent upon the design of the nose cone—usually in a range of from approximately 100 mm to 400 mm.
Necessary to give an automatic central buffer coupling of the type specified at the outset the additional functionality of axial extendability is, for example, a linear drive, with which the central buffer coupling, the coupling arm of the central buffer coupling respectively, can be axially displaced along with the coupling head relative the vehicle underframe or relative the fixing plate serving to secure the central buffer coupling to the vehicle respectively. Since the mounting space in the vehicle nose cone for the automatic central buffer coupling is often limited, however, the linear drive provided to axially displace the central buffer coupling so as to realize the additional desired functionality of axial extendability and retractability for the central buffer coupling needs to be realized in as compact and space-saving a manner as possible.
Based on this problem, it is necessary to find an automatic central buffer coupling of the type cited at the outset which exhibits the additional functionality of axial extendability and retractability without the need to increase the space in the vehicle nose cone needed to mount the central buffer coupling.